Commutator for dynamo-electric machines



oct.- 23, 1923. 1;472,o23

l.. E. Koos COMMUTATOR FOR DYAMOA ELECTRIC MACHINES Original Filed July 22. 1918 L@ lof/M f/*Il L// Vf@ \1 V* aww/vdo@ aw/ence E. /foos @How A Patented Ot. 23, 1923.

l UNITED STATES LAWRENCE E. KOOS, OF TOLEDO, OHIO.

COMIUTATOB FOR DYNAMO-ELECTBIC MACHINES.

Application llled July 22, 1918, Serial No. 246,217. Renewed March 20, 1923.

To all whom it may concem:

Be it known that I, LAWRENCE E. Koos, a citizen of the United States, residin at Toledo, in the county of Lucas and tate of Ohio, have invented certain new and' useful Improvements in Commutators for Dynamo-Electric Machines, of which I declare the following to be a full, clear, and exact description.

This invention relates to commutators for` d namo electric machines, and more particu arly to the type of commutator element which is formed of two or more elements.

The chief object of the invention is to provide a type of commutator element which will-permit of a large reduction in production cost.

Another vobject is to utilize a type of commutator element which may be assembled into the complete commutator unit with considerable ease.

Still another object is to employ a design of segment which will permit of the use-of substantially the entire blank used in the manufacture of various parts, thereby reducing the wastage of metal to a 1ninimum.

Further objects of this invention relate to economies of manufacture and details ot' construction as vwill hereinafter appear from the detailed description to follow. I accomplish the objects of my invention in one instance by the 'devices and means described in the following specification, but it is evident that the same may be varied widely without departing from the scope of the invention as pointed out in the appended claims. A structure constituting one embodiment of .m invention, which may be the preferred, 1s illustrated in the accompanying dra-wings forming a part thereof, in which:

Figure I is a perspective view of a metal blank'used in the process of manufacture.

Figure II shows the blank with the variou's commutator elements stamped out froml the blank.

Figure III isa perspective view of a single commutator element after it is stamped from the blank. f Figure IV .is a perspective View of a 'completed element. f

'Figure' V is a cross-section of the complete commutator, taken along the line V-V -y of Figure VI, and

Figure. VI is a. longitudinal' section through the commutator, taken along line VI--VI of Figure V.

In the. drawings, similar reference nu merals refer to similar parts throughout the several views, and the sectional views are taken looking in the direction of the small arrows at the ends of the sectional lines.

It has been customary heretofore,.in commutator construction, to form" the conducting bars of a commutator in two longitudi nal segments or elements, which are fitted side by side, giving in effect, a single element as far as its mechanical and electrical properties are concerned. Thisl construction -has been particularly advantageous where the necessary thickness of the bar employed has been too great for an easy punch press operation, since each of the cooperative elements may be separately punched out to the appropriate size, and then -fittedinto position.

`A disadvantage resulting from the punch press process of forming the bar elements, has been the considerable wastage of metal `cut out from the blank, due to the fact that the portion of the commutator element which serves as a connector to the armature windings, extends at right anglesto the length of the bar.4

In my construction, I utilize a.A blank in the form of a strip of metall, having a thicknessappropriate for the size of commutator segment for which it is to be ernployed. One side 2 of this strip is plain and the other side 53 has a surface formed of three plane faces, the two outer faces 4' and ,5 being of equal width and inclined slightly toward the middle of the strip.V The intermediate face 6 is parallelto the plane face 2 and adjoins the sloping faces 4 and 5 with perpendicular walls 7 and 8 'of relatively narrow width, thus forming a channel ex-v tending along the center of the face 3. The width of this channel is slightly less than that of the ysloping faces-4 and 5, this width,

however, being entirely dependent upon the necessities characteristic of the particular commutator requirements. In cross section, therefore. a figure is formed, having a straight plane side, two short parallel edges, and thek second side having five lines, the outer two ofwhich converge toward the base line, the third line of .which is depressed,

and is parallel to the base line, and the fourth and fifth lines of which connect the de ressed line with the two converging lines.

he form of commutator element is indicated in Figure III. It consists in a lonitudiually extended bar, having a top or earing surface 9, and sides 10 and 1l. From the base 12 of this bar, an integral holding or supporting portion projects, which has a base 13 parallel to the top 9 of the bar, and edges 14 and 15 projecting inwardly and conver ing from t e base 13, forming with tpe bo y portion 10, two regular dove-tailed s ots.

One end of the bar extends further to the side of the holding portion than the other.

The object of having this increased extension on one Side of the holding portion is to permit the bar to be upturned at this point., as A'shown in Fig. IV, the upturned portion 17 forming the base for the connection to the armature windings.

The commutator elelnent, as shown in the form o f Figure III, is stamped out of the bar of the blank 1, by a punch press operation, permitting of alternate formation of the elements of mutually co-acting form, as illustrated in Fi re II. The connecting portion 17 has not yet been upturned and because of the particular shape resulting, it is at once apparent that large economy ot material can be attained. The portion 17 is now upt'urned when the elements are ready for assemblage. Due to the fact that one side of each element is plain, two separate elements may be fitted together withtheir plain sides adjacent, thus forming a completed commutator segment. The various segments are then assembled in the commutator, as illustrated in Figures V and VI. where they are held upon the'core 18, by means of washers 19 and 20, and appropriately insulated therefrom by means ot insulation strips 21 and 22. fWVhen completely assembled, the adjacent terminal Vsecuring projections 17 are recessed, as shown at 2.3 of Figure V, by an appropriate sawing operation, thus forming holding recesses for the armature terminals.

It should be noted that by forming the blank with a narrow central portion. the amount of metal used in the body of the commutator is materially decreased, as illustrated at 24 of Figure V. This construction also permits of more ready assemblage of the component elements of the commutator without straining or warping.

Iam aware that the particular embodiment of my invention, herein shown and described, is susceptible of considerable variation without departing from the spirit thereof, and, therefore, I desire to claim the same broadly, as well as specifically, as indicated by the appended claims.

'Having thus described my invention, what I claim as new and desire to secure by Letters latent, is:

l. In a commutator for a dynamo electric machine a homogeneous two-part segment, each part comprising a holding portion and a body portion, said holding portion having parallel side faces and said body portion havingconverging side faces, the thickness of said body portion being at all points, greater than the thickness of Said holding portion.

2. In a commutator for dynamo electric machines, a two-part segment, each part comprising a holding portion and a body pdrtion, said holding portion having parallel side faces and said body portion having converging side faces, one of the side faces of said holding portion and one of the side faces of said body portion being in the same plane.

3. In a commutator, a composite segment comprising a pair of similar contiguous elements, each having a body portion and a holding portion, each said holding portions having a longitudinal recess at its contiguous side thereby forming a channel through the interior of the segment.

4. In a commutator for dynamo electric machines, a two-part homogeneous segment therefor, each part comprising a holding portion and a body portion, said body portion having converging sides, and said holding portion having parallel sides, one of the sides of both body portion and holding portion being in the same plane and the thickness of the body portion being greater at all points than the holding portion.

5. An article of manufacture, consisting of a strip of metal forming a blank from which commutator segments for dynamo electric machines may be cut, having a uniform cross-sectional area. one plane side and two plane edges at right angles to the plane side, and the other side of which has a central depressed longitudinally extending portion and outer enlarged longitudinally extending portions having surfaces disposed at angles tothe first mentioned side.

6. A blank from which commutator segments maybe cut, consisting in a metal strip, the cross-section of which forms a geometric ligure having two parallel sides and two other sides, one of which is straight and the other of which has a central depressed portion and two outer enlarged portions, the surf-aces of which incline from the parallel sides toward the straight side, the thickness of the strip through the enlarged portions being at all points greater than that through the depressed portion.

7. The method of forming commutator segments which consists in punching from anappropriate blank elements each comprlsmg a body portion, a holdin portion and a connecting portion and in su equent- 1y bending said connectin portion to a posltion substantially at rig t angles to said body ortion.

commutator bar, comprising two elements, each element having a holding portion with parallel sides and a body portion with sides converging toward the holding portion, the two elements being in juxtaposition and having adjacent surfaces of the body portions in contact and an aperture between the holding ortions.

9. A commutator or dynamo electric ma- 'chine comprising a plurality of segments each formed of a pair of similar members, each member having one portion with radial sides and another portion with substantially parallel sides, the thickness of the latter portion being such that a closed channel is formed through each segment.

10. A commutator for a dynamo-electric machine comprising aplurality of segments each consisting of a pair of contiguous members having longitudinal recesses formed in the contiguous sides thereof to form closed channels-through said segments.

11. A blank from which commutator segments may be cut consisting of a metal strip having two outer portions which taper from the outer edges toward the middle and an intermediate thinner portion.

l2. A blank from which commutator segments may be out consisting of a metal strip having two outer portions which taper from the outer edges toward the middle and an intermediate portion of uniform thickness but less than the thinnest part of said outer portions.

13. A blank from which commutator segments are adapted to be cutl consisting of a metal strip divided longitudinally into three portions, the two outer portions being similar and tapering from the outer edge toward the center and the third portion being intermediate and thinner than the two outer portions, said striphaving a flat side common to all said portions.

In testimony whereof, I ailix my signature.

LAWRENCE E. KOOS. 

